Starter assembly for a gas discharge lamp

ABSTRACT

The present invention comprises a unique starter assembly for a gas discharge lamp. The starter assembly comprises a main current path with a first leg connected to one electrode of a gas discharge lamp, and a second leg connected to a second electrode of the gas discharge lamp. A starting current path is provided between the first and second electrode, and comprises an magnetic switch. The magnetic switch is actuated by an electromagnet controlled by a control circuit. The control unit may be programmed with the start time required for a particular lamp design. In an alternative embodiment, the starter assembly further comprises a radio frequency identification system. The radio frequency identification system includes a gas discharge lamp transponder. The lamp transponder is used to communicate specific lamp information to the control circuit. The control circuit may then modify the start time for that lamp based on this information.

The present invention claims benefit under 35 USC §119(e) of U.S.provisional patent application Ser. No.: 60/357,908, entitled “Point OfUse Water Treatment System” filed on Feb. 19, 2002.

This application hereby incorporates by reference U.S. patentapplication Ser. No.: 10/133,860 entitled “Inductively Powered LampAssembly,” filed on Apr. 26, 2002, U.S. patent application Ser. No.:90/592,194 entitled “Fluid Treatment System”, filed on Jun. 12, 2000,U.S. patent application Ser. No.: 10/246,155 entitled “InductivelyCoupled Ballast Circuit”, filed on Sep. 18, 2002, and issued U.S. Pat.No. 6,436,299, entitled “Water Treatment System with an InductivelyCoupled Ballast”.

TECHNICAL FIELD

The present invention relates to a starter for a gas discharge lamp, andmore particularly, to a starter assembly having a magnetic switch andcontrol circuit used to start a gas discharge lamp.

BACKGROUND OF THE INVENTION

The present invention relates to starters for gas discharge lamps, andin particular to a starter assembly having a magnetic switch forstarting a lamp. Traditionally, gas discharge lamps used a specialstarter switch mechanism to start the lamp. When the lamp is firstturned on, electricity flows through a bypass circuit and across astarter switch and through the lamp electrodes. This electricitypreheats the electrodes, ionizing the gas in the lamp, thereby creatingan electrically conductive medium. After the electrodes are heatedsufficiently, the starter switch opens, causing the lamp ballast toprovide a voltage surge, and the electric current to arc through the gasdischarge lamp. The conventional starter switch uses a small dischargebulb containing neon or some other gas. The bulb has two electrodespositioned adjacent to each other. Current arcs between the electrodes,causing a small amount of heat to build within the bulb, which causesone bimetallic electrodes to bend so that it makes contact with theother electrode. When the two electrodes make contact, the current nolonger arcs between the electrodes. Consequently, there are no chargedparticles flowing through the gas. Without the heat from the chargedparticles, the bimetallic electrode cools, bending away from the otherelectrode. This opens the circuit, causing the ballast to transferenergy to the lamp electrodes, and subsequently causing the lamp toignite. When the current flows through the bypass circuit, itestablishes a magnetic field in part of the lamp ballast. This magneticfield is maintained by the flowing current. When the starter switch isopened, the current is briefly cut off from the ballast. The magneticfield collapses, which creates a sudden jump in current causing theballast releases its stored energy and light the gas discharge lamp.

Other gas discharge lamps rely on a design that does not include astarter switch. Instead, the lamp's ballast constantly channels currentthrough both electrodes. This current flow is configured so that thereis a charge difference between the two electrodes, establishing avoltage across the lamp.

Alternatively, gas discharge lamps may rely on a high initial voltage tothe lamp electrodes, producing a corona discharge used to start thelamp. Excess electrons on the lamp electrode surface forces someelectrons into the gas. These free electrons ionize the gas, and almostinstantly the voltage difference between the electrodes establishes anelectrical arc.

A first problem with the above starter designs is that they are unableto accommodate variations in lamp preheat requirements. A particularstarter must be designed for the preheat requirements of a particulargas discharge lamp or narrow range of gas discharge lamps. A secondproblem with the above starter designs is that they are unable to adaptto variations in gas discharge lamps caused by variations in lampmaterials and lamp construction. These variations can cause a change inthe preheat requirements for the lamp. This change may result in achange in the lamp starter design, or a discarding of off-specificationlamps. Another problem with the above starter designs is that they areunable to accommodate changes in gas discharge lamp preheatrequirements, particularly as these gas discharge lamps change with useand age. The starter assembly of the present invention overcomes, orminimizes these, and other problems associated with conventional gasdischarge lamp starters.

SUMMARY OF THE INVENTION

The present invention comprises a unique starter assembly for a gasdischarge lamp. The starter assembly includes a current path with afirst leg connected to a first electrode of a gas discharge lamp, and asecond leg connected to a second electrode of the gas discharge lamp.The current path comprises an magnetic switch. The magnetic switch isactuated by an electromagnet controlled by a control circuit. Thecontrol unit may be programmed with the preheat time required for thegas discharge lamp. In an alternative embodiment, the control unit maybe programmed with a range of preheat times for a gas discharge lamp.According to this embodiment, the control unit may be provided withpreheat times that increase in duration with each start of the lamp orin the alternative, increase in duration as the lamp ages.

In another alternative embodiment, the starter assembly is furthercomprised of a control unit and a radio frequency identification system.The radio frequency identification system includes a transponder coupledwith the gas discharge lamp. The radio frequency identification systemobtains information about the lamp from the lamp transponder. Thisinformation is then provided to the control circuit. The control circuitmay modify the preheat time for that lamp based on this information.Those skilled in the art would recognize that alternative non-contact,as well as contact-type identification systems may be used instead ofthe radio frequency identification system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a lamp assembly according to oneembodiment of the present invention;

FIG. 2 is a sectional view the lamp assembly of FIG. 1 takenperpendicularly to the sectional view of FIG. 1;

FIG. 3 is a schematic diagram of the lamp circuit of the illustratedembodiment;

FIG. 4 is a schematic of the starter circuit of the illustratedembodiment;

FIG. 5 is a schematic of the starter circuit and radio frequencyidentification system of the illustrated embodiment;

DETAILED DESCRIPTION OF INVENTION

The present invention is not limited in its application to the detailsof construction and arrangement of parts as illustrated in theaccompanying drawings and specifications. Although described inconnection with this particular application, one skilled in the artswould recognize that the present invention is capable of being practicedin various ways within the scope of the claims. In addition, althoughthe magnetic starter circuit of the present invention is illustrated asused with a ultra violet lamp, one skilled in the art would recognizethat the present invention is capable of being used in connection withany type of gas discharge lamp that utilizes a starter circuit.

I. Lamp Configuration

A gas discharge lamp assembly according to one embodiment of the presentinvention is shown in FIGS. 1 and 2, and is generally designated 10. Forpurposes of disclosure, the present invention is described in connectionwith a conventional type PL-S 11 watt ultra violet (UV) lamp convertedfor use at 38 watt, such as the type described in U.S. patentapplication Ser. No. 10/133,860 filed on Apr. 26, 2002, entitled“Inductively Powered Lamp Assembly”, the subject matter of which ishereby incorporated in its entirety by reference. The lamp assembly 10generally includes a lamp circuit 12 and an outer sleeve 70. In thisembodiment, the lamp circuit 12 includes a single secondary 14,preferably in the form of a coil of small diameter wire 22. Thesecondary 14 inductively receives power from the primary (not shown) ofan associated ballast (not shown). The entire lamp circuit 12 and lamp18 is fully enclosed within the outer sleeve 70. In the illustratedembodiment, at least a portion of the outer sleeve 70 is transparent andis not penetrated by electrical wires or other elements. Outer sleeve 70preferably includes a main body 90 and a cap 92. The main body 90 is agenerally cylindrical tube having an open end and a closed end. Afterthe lamp circuit 12 is installed within the main body 90, the cap 92 issealed over the open end of the main body 90 to fully enclose the lampcircuit 12. The lamp 18 is a generally conventional PL-S type lamphaving a quartz sleeve with two parallel legs 72 a-b that areinterconnected to cooperatively define a chamber 28. The chamber 28 ispartially evacuated and contains the desired electric-discharge gas,such as mercury vapor. A stem 32 a-b is located at the base of each leg72 a-b. A pair of conventional or custom designed electrodes 36 a-b aredisposed within the chamber 28, one mounted atop each of the stems 32a-b. In this embodiment, the outer sleeve 70 is preferably manufacturedfrom quartz to permit the efficient passage of UV light. In non-UVapplications, the outer sleeve may be manufactured from glass, Teflon orplastic, depending in part on the heat generated by the lamp and theoperating environment of the lamp. For example, an alternative outersleeve can be manufactured from a length of Teflon tubing having sealedopposite ends (not shown). The Teflon tubing can be fitted over theremainder of the lamp assembly, and its opposite ends can be crimped orotherwise sealed to close the Teflon sleeve. Preferably, each end of theTeflon tubing is folded back onto itself and crimped using heat andpressure.

With further reference to the figures, and in particular FIGS. 1 and 2,lamp assembly 10 also includes a base 50 and a support 86 that holdopposite ends the lamp 18 within the outer sleeve 70. The base 50 isgenerally cylindrical and dimensioned to be fitted closely within theouter sleeve 70. In addition to holding one end of the lamp 18, the base50 also receives capacitor 16 and magnetic switch 34 as described inmore detail below. The base 50 defines an annular recess 80 to receivethe windings of the secondary 14, and a pair of apertures 82 a-b toreceive the base end of each leg 72 a-b and a pair of voids 84 a-b tocontain the capacitor 16 and magnetic switch 34 or transponder 126 asdescribed in more detail below. The lamp assembly 10 may also include aheat reflector 58 disposed between the secondary and the electrodes 36a-b. The heat reflector 58 is preferably shaped to match thecross-sectional shape of the lamp sleeve 52 at the point where it ismounted, and is preferably manufactured from a conventional reflectivematerial, such as aluminum or aluminum foil on a suitable substrate. Thesupport 86 is generally disc-shaped and is dimensioned to be fittedclosely within the outer sleeve 70. The support 86 preferably includes atab 88 to be frictionally fitted between the legs 72 a-b of the quartzsleeve 52. The precise design and configuration of the base 50 andsupport 86 can vary among applications depending on the design andconfiguration of the outer sleeve 70 and the various components of thelamp circuit 12. The base 50 and support 86 are preferably manufacturedfrom materials capable of withstanding high heat, such as ceramic orhigh temperature plastics.

A wide variety of ballasts capable of powering the inductive lampassembly 10 are well known to those skilled in the field. Accordingly,the ballast will not be described in detail. One ballast particularlywell-suited for use with the lamp of the illustrated embodiment isdisclosed in U.S. patent application Ser. No.: 10/246,155 entitled“Inductively Coupled Ballast Circuit”, filed on Sep. 18^(th), 2002,which is incorporated in its entirety herein by reference. This ballastcan be readily adapted to provide efficient operation of the disclosedembodiments of the present invention.

II. Starting Circuit

Referring to the figures, and in particular to FIGS. 3 and 4, thestarter assembly of the illustrated embodiment is shown in conjunctionwith the UV lamp assembly 10 described above. Lamp circuit 12 iscomprised of electrodes 36 a-b, capacitor 16, secondary coil 14, andmagnetic switch 34. One typical lamp circuit suited for use with themagnetic starter assembly of the present invention is described in U.S.patent application Ser. No.: 10/133,860 entitled “Inductively PoweredLamp Assembly,” filed on April 26, 2002 and incorporated in its entiretyherein by reference.

With further reference to FIGS. 3 and 4, magnetic switch 34 is wired inseries between the electrodes 36 a-b and is actuated by electronicsmodule 100. Electronics module 100 is comprised of control unit 102,resistor 104, FET 106, diode 108, and electromagnet 110. Electromagnet110 is positioned proximate to magnetic switch 34 where, when charged,it can selectively close switch 34. Control unit 102 controls operationof electromagnet 110. Control unit 102 is programmed, using methodsknown in the arts, to charge electromagnet 110 for a fixed interval oftime, or “preheat time” each time that lamp circuit 12 is powered on.According to the illustrated embodiment, lamp ballast (not shown)provides power from a primary coil (not shown) to secondary coil 14.Lamp ballast (not shown) also provides a lamp start signal to controlunit 102. Control unit 102 then utilizes a 5 volt signal to close FET106, creating a 165 volt charge across electromagnet 110. This chargecauses electromagnet 110 to generate a magnetic field which closes themagnetic switch 34, thereby causing current from secondary coil 14 toflow directly through the electrodes 36 a-b, rather than through legs 72a-b. As a result, electrodes 36 a-b are rapidly heated. After the fixedinterval of preheat time, control unit 102 opens FET 106, causingde-energizing of electromagnet 110. De-energizing of electromagnet 110causes the opening of switch 34, which, in turn, causes current to flowthrough legs 72 a-b between electrodes 36 a-b. Opening of switch 34often provides a voltage surge from the lamp ballast (not shown) used tostart gas discharge lamp 18. Magnetic switch 34 is preferably arrangedsubstantially perpendicular to the field of the ballast primary coil(not shown) so that the magnetic switch 34 is not actuated by themagnetic field of the primary coil (not shown). Magnetic switch 34 ofthe illustrated embodiment is a normally open magnetic reed switchmanufactured by Coto, part number RI-48A, although one skilled in theart would recognize that any substantially similar magnetic switch wouldfunction equivalently. The preheat time interval for lamp assembly 10 ofthe illustrated embodiment is 400 milliseconds, although one skilled inthe arts would recognize that this preheat time may vary betweendifferent lamp configurations, and between lamps of the sameconfiguration. Electromagnet 110 of the illustrated embodiment iscomprised of an Elytone coil, part number YT-50054-1. Although shownwith an FET, one skilled in the arts would recognize that any relaydevice could be used to apply power to electromagnet 110. Control unit102 of the illustrated embodiment is comprised of a Microchip TechnologyInc. microprocessor, part number 18F452.

III. Alternative Embodiments

An alternative embodiment of the magnetic starter assembly of thepresent invention further comprises a Radio Frequency Identification(RFID) system. Referring to FIG. 5, lamp assembly 10 of the illustratedembodiment is further comprised of transponder 126, and electronicsmodule 100 is further comprised of RFID circuit 124. RFID circuits areknown in the arts, with an exemplary RFID circuit described in U.S. Pat.No. 6,436,299 entitled “Water Treatment System with an InductivelyCoupled Ballast”, the contents of which is hereby incorporated in itsentirety by reference. The RFID circuit allows contactless reading ofdata, which is transmitted from transponder 126 to control unit 102, or,in an alternative embodiment, bidirectionally between the transponder126 and control unit 102.

The radio frequency identification system 124 is used by the controlunit 102 to obtain information specific to UV lamp assembly 10. Sincethe UV lamp radio frequency identification transponder 126 is located inthe UV lamp assembly 10, these devices are never separated, which allowsthe control unit 102 to read or write information to and fromtransponder 126 through the base station 360.

Referring again to FIG. 5, the UV lamp radio frequency identificationtransponder 126 includes a transponder antenna 362 and a read/writeIDIC® (e5551) chip 364. The read/write IDIC® (e5551) chip furtherincludes an EEPROM device 366 that physically stores the relevantinformation for each respective UV lamp assembly 10 in memory locations.In the presently preferred embodiment, the information consists of anultraviolet lamp serial number and ultraviolet lamp preheat time.

The ultraviolet lamp serial number is unique to each ultraviolet lampassembly 10. The ultraviolet lamp preheat time relates to the amount oftime the ultraviolet lamp 18 needs to be preheated.

The radio frequency identification system 124 includes the base station360, a coil 380, a plurality of diodes 382, 384, 386, 388, 390, 392,394, a plurality of resistors 396, 398, 400, 402, 404, 406, 408, 410,412, 414, 416, 418, 420 and a plurality of capacitors 422, 424, 426,428, 430, 432, 434, 436 that are electrically connected as illustratedin FIG. 5. Those skilled in the art would recognize that the connectionof the aforementioned components is well known to those skilled in theart. The radio frequency identification system 124 has been installed inelectronics module 100 using specifications set forth for theTK5551A-PP, which, as previously set forth, is manufactured by TEMICSemiconductors. For the purpose of the present invention, it isimportant to note that the base station 360 uses the coil 380 forbidirectional communication with the ultraviolet light radio frequencyidentification transponder 126. The control unit 102 is electricallyconnected with the base station 360 so that the control unit 102 cancommunicate with the base station 360. Radio frequency identificationsystem 124 is connected with the first DC power source 180 and thesecond DC power source 184 as illustrated in FIG. 5, which provides theradio frequency identification system 124 with energy to function duringoperation.

In one alternative of the illustrated embodiment, stored in EEPROMdevice 366 is programmed with lamp assembly 10 serial number usingmethods well known in the arts. Upon start-up of lamp assembly 10, radiofrequency identification system 124 retrieves the serial number for lampassembly 10 from transponder 126. Lamp assembly 10 serial number iscommunicated to control unit 102 by base station 360. Using methodsknown in the art, control unit 102 then refers to a pre-programmedlook-up table to determine the preheat time for that particular lampassembly based on the retrieved serial number from transponder 126.Control unit 102 activates electromagnet 110 for the preheat timespecified, thereby preheating elements 36 a-b prior to starting lampassembly 10.

In a second alternative of the illustrated embodiment, stored in EEPROMdevice 366 is programmed with lamp assembly 10 serial number usingmethods well known in the arts. EEPROM device 366 is further configuredto store the number of starts for each lamp assembly 10 started by thestarter assembly of the present invention. Upon start-up of lampassembly 10, radio frequency identification system 124 retrieves theserial number for lamp assembly 10 from transponder 126. Lamp assembly10 serial number is communicated to control unit 102 by base station360. Control unit 102 then refers to a pre-programmed look-up tablestored in EEPROM device 366 to determine the preheat time for that lampassembly 10 based on the lamp assembly 10 serial number and total numberof lamp assembly 10 starts. After lamp assembly 10 has been started,control unit increments the total number of lamp assembly 10 startsstored in stored in EEPROM device 366. In one embodiment of the presentinvention, the preheat time for lamp assembly 10 is increased as thenumber of starts increases.

In another alternative embodiment, stored in EEPROM device 366 isprogrammed with the preheat for lamp assembly 19 using methods known inthe arts. Upon start-up of lamp assembly 10, radio frequencyidentification system 124 retrieves the preheat for lamp assembly 10from stored in EEPROM device 366. Lamp assembly 10 preheat iscommunicated to control unit 102 by base station 360. Control unit 102then uses this preheat time to energize electromagnet 110 each time lampcircuit 12 is powered on.

Those skilled in the art would recognize that other identificationsystems could be used with the present invention, such as contact-typeidentification systems. However, the present preferred embodiment of theinvention uses a radio frequency identification system 124 because ofthe inherent benefits such a system provides.

The configuration of the magnetic starter assembly may vary materiallyfrom application to application depending largely on the type of lampand the associated power requirements. The present invention can bereadily modified to permit use with a wide variety of existing lightingsystems. The above description is that of various embodiments of theinvention. Various alterations and changes can be made without departingfrom the spirit and broader aspects of the invention as defined in theappended claims, which are to be interpreted in accordance with theprinciples of patent law including the doctrine of equivalents. Anyreference to claim elements in the singular, for example, using thearticles “a”, “an”, “the”, or “said”, is not to be construed as limitingthe element to the singular.

What is claimed is:
 1. A starter assembly for a gas discharge lampcomprising at least two electrodes, the starter assembly comprising: anormally open magnetic switch connected in series between the at leasttwo electrodes of the gas discharge lamp an electromagnet operable toclose the normally open magnetic switch; a programmable microprocessoroperable to control the operation of the electromagnet; wherein themicroprocessor is programmed to operate the electromagnet for a firstpredetermined length of time, thereby closing the magnetic switch for afirst predetermined length of time.
 2. The starter assembly of claim 1,wherein the microprocessor is further programmed to operate theelectromagnet for a second predetermined length of time.
 3. A starterassembly for a gas discharge lamp assembly, the starter assemblycomprising: at least one switch located in series between at least twoelectrodes of the gas discharge lamp; a control unit operable foractuating the switch; a base station electrically connected to saidcontrol unit; and at least one radio frequency identificationtransponder located in the gas discharge lamp assembly that is in radiocommunication with the base station, wherein the control unit actuatesthe switch according to information received from the transponder. 4.The starter assembly of claim 3, wherein said radio frequencyidentification transponder includes a responder antenna and a read/writechip.
 5. The starter assembly of claim 2, wherein said radio frequencyidentification transponder is capable of transmitting a gas dischargelamp serial number to said base station for use by said control unit. 6.The starter assembly of claim 3, wherein said radio frequencyidentification transponder is capable of transmitting a gas dischargelamp preheat time to said base station for use by said control unit. 7.The starter assembly of claim 3, wherein said radio frequencyidentification transponder allows said control unit to keep track of gasdischarge lamp starts.
 8. The starter assembly of claim 3, wherein theswitch is a normally open magnetic switch.
 9. The starter assembly ofclaim 8, wherein the control unit further comprises an electromagnetoperable to close the magnetic switch.
 10. A method of starting a gasdischarge lamp comprising the steps of: connecting a normally openmagnetic switch in series with at least two electrodes of gas dischargelamp; closing said magnetic switch for a predetermined length of timewith an electromagnet; providing electric current through the electrodesand the magnetic switch during the predetermined length of time.
 11. Themethod of claim 10 further comprising the step of controlling the amountof time that the magnetic switch is closed with a programmablemicroprocessor.
 12. The method of further comprising the steps ofvarying the amount of time that the magnetic switch is closed.
 13. Themethod of claim 10 further comprising the steps of retrievinginformation about the gas discharge lamp from a transponder located inthe gas discharge lamp.
 14. The method of claim 13 further comprisingthe steps of modifying the duration of time that the magnetic switch isclosed based on the information retrieved from the transponder.